An on-line advertising system may provide advertising links (also referred to as “impressions” hereinafter) to users when they visit certain web pages. When a particular advertising link is of interest to a user, a user may select (or click) the advertising link, which may cause the user's web browser to visit a web page belonging to the advertiser associated with the advertising link. This selection of an advertising link by a user is commonly referred to as a “click.”
On-line advertising systems often track impressions and clicks, and calculate charges based thereon. For example, an on-line advertising system may calculate a charge based, at least in part, on the clicks that an advertising link receives. Charges may also be calculated based on other characteristics as well, such as time of day, location of the user, age or other demographic information associated with the user, or the like.
On-line advertising systems may charge companies a predetermined fee for each click or impression associated with the companies' advertisements. The on-line advertising system may also pay a fee to the web publisher that displays an advertising link for each click that the advertising link receives or each advertising link impression. These types of fee approaches are vulnerable to attacks where malicious individuals inflate a company's advertising link click count or impression count. For example, malicious individuals may continually cause the company's advertisement(s) to be displayed, physically click on the company's advertisement(s), and/or write programs (often called click-bots or impression-bots) that automatically generate page views and/or clicks. These click-bots can be configured to mimic real network traffic by specifying parameters, such as clicks to page view distributions, geographic locations and network addresses, amount of traffic by days of the week and time of day, etc.
When malicious advertising activity occurs, a company may be charged for clicks or impressions that do not correspond to actual (or real) users. This can result in inaccurate fees being charged for advertising services. In those situations where web publishers are paid a fee each time a displayed advertising link is clicked or displayed, the web publishers themselves may use bots or malicious individuals to increase their revenue from the on-line advertising systems.